A touch panel built in a liquid crystal display is integrated with a color filter substrate to effectively reduce the thicknesses of the entire touch display device and simplify the manufacturing process of the touch display device, and hence has been widely applied. In general, a touch can be monitored by detecting the capacitance of a mutual capacitor formed by two metal layers and one organic film layer which are integrated on the color filter substrate. Here, a touch detection signal is transmitted to the color filter substrate by a conductive pad through a gold ball bond on an array substrate.
Particularly, as shown in FIG. 1, an in-cell touch panel 100 in the prior art includes: an in-cell touch color filter substrate, an array substrate 102 that is adhered to the color filter substrate by a sealant 104, and a liquid crystal layer 103 disposed between the in-cell touch color filter substrate and the array substrate 102. The color filter substrate includes a substrate 105, as well as a black matrix 106, a first metal layer 107, a first organic film layer 108, a second metal layer 109, a color filter layer 110 and a second organic film layer 111 that are formed on the substrate 105 successively. The first metal layer 107 includes a plurality of upper conductive pads 112, a lower conductive pad 113 corresponding to the upper conductive pads 112 is formed on the array substrate, and a conductive sealant 114 is filled between the upper conductive pads 112 and the lower conductive pad 113. A gold ball bond 115, by which the array substrate 102 and the color filter substrate are electrically connected, are mixed in the conductive sealant 114.
In the prior art, a first through hole 116 is formed in the first organic film layer 108 at a position corresponding to the upper conductive pads 112. Likewise, a second through hole 117 is formed in the second organic film layer 111 at a position corresponding to the first through hole 116. The upper conductive pads 112 are connected with the lower conductive pad 113 by the gold ball bond 115 passing through the first through hole 116 and the second through hole 117. Generally, the thickness of each of the first organic film layer 108 and the second organic film layer 111 is about 2 μm, thus, the gold ball bond 115 contacts with the upper conductive pads 112 only after passing through the holes with a depth above 4 μm. In order to allow the gold ball bond 115 to enter the second through hole 117 precisely, the applied conductive sealant 114 must cover the upper conductive pads 112 precisely.
Compared with the overlying precision of the sealant 104, the overlying precision of the conductive sealant 114 shall be higher. In order to save production time, the sealant 104 and the conductive sealant 114 are applied in different speeds. Because of the higher applying precision of the conductive sealant 114, the conductive sealant 114 is applied separately from the conductive sealant 114 in a low speed. Therefore, a relatively long time is required for completing the applying.